Optical imaging lens and electronic device comprising the same

ABSTRACT

An optical imaging lens set includes a first lens element to a sixth lens element from an object side toward an image side along an optical axis. The first lens element has negative refractive power. The second lens element has an object-side surface with a convex portion in a vicinity of periphery. The third lens element has an object-side surface with a convex portion in a vicinity of periphery. The fifth lens element has an image-side surface with a convex portion in a vicinity of the optical axis. The sixth lens element has an object-side surface with a concave portion in a vicinity of its periphery.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to Taiwan Application No. 102139575,filed on Oct. 31, 2013.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an optical imaging lens setand an electronic device which includes such optical imaging lens set.Specifically speaking, the present invention is directed to an opticalimaging lens set of reduced length and an electronic device whichincludes such optical imaging lens set.

2. Description of the Prior Art

In recent years, the popularity of mobile phones and digital camerasmakes the sizes of various portable electronic products reduce quicklyso does the photography modules. The current trend of research is todevelop an optical imaging lens set of a shorter length withuncompromised good quality. The most important characters of an opticalimaging lens set are image quality and size.

U.S. Pat. No. 7,580,205 discloses a wide-angle optical imaging lens setmade of six lens elements. To pursue better image quality, more lenselements are used so the total length of the optical imaging lens set isup to 20 mm or more. Such bulky optical imaging lens set is not suitablefor an electronic device of small size.

It is still a problem, on one hand, to reduce the system lengthefficiently and, on the other hand, to maintain a sufficient opticalperformance in this field.

SUMMARY OF THE INVENTION

In the light of the above, the present invention is capable of proposingan optical imaging lens set of lightweight, low production cost, reducedlength, high resolution and high image quality. The optical imaging lensset of six lens elements of the present invention has a first lenselement, a second lens element, a third lens element, a fourth lenselement, a fifth lens element and a sixth lens element sequentially froman object side to an image side along an optical axis. The first lenselement has negative refractive power. The second lens element has asecond object-side surface with a convex portion in a vicinity of itscircular periphery. The third lens element has a third object-sidesurface with a convex portion in a vicinity of its circular periphery.The fourth lens element has refractive power. The fifth lens element hasa fifth image-side surface with a convex portion in a vicinity of theoptical axis. The sixth lens element has a sixth object-side surfacewith a concave portion in a vicinity of its circular periphery. Theoptical imaging lens set exclusively has six lens elements withrefractive power.

In the optical imaging lens set of six lens elements of the presentinvention, a distance L_(tt) from the first object-side surface to animaging plane on the image side along the optical axis and an air gapG₂₃ between the second lens element and the third lens element along theoptical axis satisfy a relationship L_(tt)/G₂₃≦20.0.

In the optical imaging lens set of six lens elements of the presentinvention, a thickness T₅ of the fifth lens element along the opticalaxis satisfies a relationship L_(tt)/T₅≦11.0.

In the optical imaging lens set of six lens elements of the presentinvention, an air gap G₂₃ between the second lens element and the thirdlens element along the optical axis satisfy a relationshipT_(all)/G₂₃≦10.0.

In the optical imaging lens set of six lens elements of the presentinvention, a distance L_(tt) from the first object-side surface to animaging plane on the image side along the optical axis satisfies arelationship L_(tt)/T_(all)≦3.0.

In the optical imaging lens set of six lens elements of the presentinvention, a thickness T₅ of the fifth lens element along the opticalaxis satisfies a relationship T_(all)/T₅≦5.0.

In the optical imaging lens set of six lens elements of the presentinvention, the sum of all five air gaps G_(aa) between each lens elementfrom the first lens element to the sixth lens element along the opticalaxis and an air gap G₂₃ between the second lens element and the thirdlens element along the optical axis satisfy a relationshipG_(aa)/G₂₃≦4.5.

In the optical imaging lens set of six lens elements of the presentinvention, a thickness T₁ of the first lens element along the opticalaxis satisfies a relationship L_(tt)/T₁≦23.0.

In the optical imaging lens set of six lens elements of the presentinvention, an air gap G₃₄ between the third lens element and the fourthlens element along the optical axis satisfies a relationshipT_(all)/G₃₄≦23.0.

In the optical imaging lens set of six lens elements of the presentinvention, a thickness T₂ of the second lens element along the opticalaxis satisfies a relationship T_(all)/T₂≦7.5.

In the optical imaging lens set of six lens elements of the presentinvention, a thickness T₁ of the first lens element along the opticalaxis satisfies a relationship L_(tt)/T₁≦23.0.

In the optical imaging lens set of six lens elements of the presentinvention, air gap G₃₄ between the third lens element and the fourthlens element along the optical axis satisfies a relationshipL_(tt)/G₃₄≦35.0.

In the optical imaging lens set of six lens elements of the presentinvention, a thickness T₂ of the second lens element along the opticalaxis satisfies a relationship L_(tt)/T₂≦17.0.

In the optical imaging lens set of six lens elements of the presentinvention, a thickness T₃ of the third lens element along the opticalaxis satisfies a relationship L_(tt)/T₃≦8.5.

In the optical imaging lens set of six lens elements of the presentinvention, a distance L_(tt) from the first object-side surface to animaging plane on the image side along the optical axis satisfies arelationship L_(tt)/G_(aa)≦5.0.

In the optical imaging lens set of six lens elements of the presentinvention, a thickness T₄ of the fourth lens element along the opticalaxis satisfies a relationship 8.5≦G_(aa)/T₄.

In the optical imaging lens set of six lens elements of the presentinvention, a thickness T₅ of the fifth lens element along the opticalaxis satisfies a relationship L_(tt)/T₅≦11.0.

The present invention also proposes an electronic device which includesthe optical imaging lens set as described above. The electronic deviceincludes a case and an image module disposed in the case. The imagemodule includes an optical imaging lens set as described above, a barrelfor the installation of the optical imaging lens set, a module housingunit for the installation of the barrel, a substrate for theinstallation of the module housing unit and an image sensor disposed atthe substrate and at an image side of the optical imaging lens set.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a first example of the optical imaging lens set ofthe present invention.

FIG. 2A illustrates the longitudinal spherical aberration on the imageplane of the first example.

FIG. 2B illustrates the astigmatic aberration on the sagittal directionof the first example.

FIG. 2C illustrates the astigmatic aberration on the tangentialdirection of the first example.

FIG. 2D illustrates the distortion aberration of the first example.

FIG. 3 illustrates a second example of the optical imaging lens set offour lens elements of the present invention.

FIG. 4A illustrates the longitudinal spherical aberration on the imageplane of the second example.

FIG. 4B illustrates the astigmatic aberration on the sagittal directionof the second example.

FIG. 4C illustrates the astigmatic aberration on the tangentialdirection of the second example.

FIG. 4D illustrates the distortion aberration of the second example.

FIG. 5 illustrates a third example of the optical imaging lens set offour lens elements of the present invention.

FIG. 6A illustrates the longitudinal spherical aberration on the imageplane of the third example.

FIG. 6B illustrates the astigmatic aberration on the sagittal directionof the third example.

FIG. 6C illustrates the astigmatic aberration on the tangentialdirection of the third example.

FIG. 6D illustrates the distortion aberration of the third example.

FIG. 7 illustrates a fourth example of the optical imaging lens set offour lens elements of the present invention.

FIG. 8A illustrates the longitudinal spherical aberration on the imageplane of the fourth example.

FIG. 8B illustrates the astigmatic aberration on the sagittal directionof the fourth example.

FIG. 8C illustrates the astigmatic aberration on the tangentialdirection of the fourth example.

FIG. 8D illustrates the distortion aberration of the fourth example.

FIG. 9 illustrates a fifth example of the optical imaging lens set offour lens elements of the present invention.

FIG. 10A illustrates the longitudinal spherical aberration on the imageplane of the fifth example.

FIG. 10B illustrates the astigmatic aberration on the sagittal directionof the fifth example.

FIG. 10C illustrates the astigmatic aberration on the tangentialdirection of the fifth example.

FIG. 10D illustrates the distortion aberration of the fifth example.

FIG. 11 illustrates a sixth example of the optical imaging lens set offour lens elements of the present invention.

FIG. 12A illustrates the longitudinal spherical aberration on the imageplane of the sixth example.

FIG. 12B illustrates the astigmatic aberration on the sagittal directionof the sixth example.

FIG. 12C illustrates the astigmatic aberration on the tangentialdirection of the sixth example.

FIG. 12D illustrates the distortion aberration of the sixth example.

FIG. 13 illustrates a seventh example of the optical imaging lens set offour lens elements of the present invention.

FIG. 14A illustrates the longitudinal spherical aberration on the imageplane of the seventh example.

FIG. 14B illustrates the astigmatic aberration on the sagittal directionof the seventh example.

FIG. 14C illustrates the astigmatic aberration on the tangentialdirection of the seventh example.

FIG. 14D illustrates the distortion aberration of the seventh example.

FIG. 15 illustrates a eighth example of the optical imaging lens set offour lens elements of the present invention.

FIG. 16A illustrates the longitudinal spherical aberration on the imageplane of the eighth example.

FIG. 16B illustrates the astigmatic aberration on the sagittal directionof the seventh example.

FIG. 16C illustrates the astigmatic aberration on the tangentialdirection of the eighth example.

FIG. 16D illustrates the distortion aberration of the eighth example.

FIG. 17 illustrates exemplificative shapes of the optical imaging lenselement of the present invention.

FIG. 18 illustrates a first preferred example of the portable electronicdevice with an optical imaging lens set of the present invention.

FIG. 19 illustrates a second preferred example of the portableelectronic device with an optical imaging lens set of the presentinvention.

FIG. 20 shows the optical data of the first example of the opticalimaging lens set.

FIG. 21 shows the aspheric surface data of the first example.

FIG. 22 shows the optical data of the second example of the opticalimaging lens set.

FIG. 23 shows the aspheric surface data of the second example.

FIG. 24 shows the optical data of the third example of the opticalimaging lens set.

FIG. 25 shows the aspheric surface data of the third example.

FIG. 26 shows the optical data of the fourth example of the opticalimaging lens set.

FIG. 27 shows the aspheric surface data of the fourth example.

FIG. 28 shows the optical data of the fifth example of the opticalimaging lens set.

FIG. 29 shows the aspheric surface data of the fifth example.

FIG. 30 shows the optical data of the sixth example of the opticalimaging lens set.

FIG. 31 shows the aspheric surface data of the sixth example.

FIG. 32 shows the optical data of the seventh example of the opticalimaging lens set.

FIG. 33 shows the aspheric surface data of the seventh example.

FIG. 34 shows the optical data of the eighth example of the opticalimaging lens set.

FIG. 35 shows the aspheric surface data of the eighth example.

FIG. 36 shows some important ratios in the examples.

DETAILED DESCRIPTION

Before the detailed description of the present invention, the firstthing to be noticed is that in the present invention, similar (notnecessarily identical) elements share the same numeral references. Inthe entire present specification, “a certain lens element hasnegative/positive refractive power” refers to the part in a vicinity ofthe optical axis of the lens element has negative/positive refractivepower. “An object-side/image-side surface of a certain lens element hasa concave/convex part or concave/convex portion” refers to the part ismore concave/convex in a direction parallel with the optical axis to becompared with an outer region next to the region. Take FIG. 17 forexample, the optical axis is “I” and the lens element is symmetricalwith respect to the optical axis I. The object side of the lens elementhas a convex part in the region A, a concave part in the region B, and aconvex part in the region C because region A is more convex in adirection parallel with the optical axis than an outer region (region B)next to region A, region B is more concave than region C and region C issimilarly more convex than region E. “A circular periphery of a certainlens element” refers to a circular periphery region of a surface on thelens element for light to pass through, that is, region C in thedrawing. In the drawing, imaging light includes Lc (chief ray) and Lm(marginal ray). “A vicinity of the optical axis” refers to an opticalaxis region of a surface on the lens element for light to pass through,that is, the region A in FIG. 17. In addition, the lens element mayinclude an extension part E for the lens element to be installed in anoptical imaging lens set. Ideally speaking, no light would pass throughthe extension part, and the actual structure and shape of the extensionpart is not limited to this and may have other variations. For thereason of simplicity, the extension part is not illustrated in theexamples.

As shown in FIG. 1, the optical imaging lens set 1 of the presentinvention, sequentially from an object side 2 (where an object islocated) to an image side 3 along an optical axis 4, has a first lenselement 10, a second lens element 20, a third lens element 30, a fourthlens element 40, a fifth lens element 50, a sixth lens element 60, afilter 70 and an image plane 71. Generally speaking, the first lenselement 10 is made of a transparent glass material, but the second lenselement 20, the third lens element 30, the fourth lens element 40, thefifth lens element 50 and the sixth lens element 60 may be made of atransparent plastic material, but the present invention is not limitedto this. There are exclusively six lens elements with refractive powerin the optical imaging lens set 1 of the present invention. The opticalaxis 4 is the optical axis of the entire optical imaging lens set 1, andthe optical axis of each of the lens elements coincides with the opticalaxis of the optical imaging lens set 1.

Furthermore, the optical imaging lens set 1 includes an aperture stop(ape. stop) 80 disposed in an appropriate position. In FIG. 1, theaperture stop 80 is disposed between the third lens element 30 and thefourth lens element 40. When light emitted or reflected by an object(not shown) which is located at the object side 2 enters the opticalimaging lens set 1 of the present invention, it forms a clear and sharpimage on the image plane 71 at the image side 3 after passing throughthe first lens element 10, the second lens element 20, the third lenselement 30, the aperture stop 80, the fourth lens element 40, the fifthlens element 50, and the sixth lens element 60 and the filter 70.

In the embodiments of the present invention, the optional filter 70 maybe a filter of various suitable functions, for example, the filter 70may be an infrared cut filter (IR cut filter), placed between the sixthlens element 60 and the image plane 71.

Each lens element in the optical imaging lens set 1 of the presentinvention has an object-side surface facing toward the object side 2 aswell as an image-side surface facing toward the image side 3. Inaddition, each object-side surface and image-side surface in the opticalimaging lens set 1 of the present invention has a part in a vicinity ofits circular periphery (circular periphery part) away from the opticalaxis 4 as well as a part in a vicinity of the optical axis (optical axispart) closer to the optical axis 4. For example, the first lens element10 has an object-side surface 11 and an image-side surface 12; thesecond lens element 20 has an object-side surface 21 and an image-sidesurface 22; the third lens element 30 has an object-side surface 31 andan image-side surface 32; the fourth lens element 40 has an object-sidesurface 41 and an image-side surface 42; the fifth lens element 50 hasan object-side surface 51 and an image-side surface 52; the sixth lenselement 60 has an object-side surface 61 and an image-side surface 62.

Each lens element in the optical imaging lens set 1 of the presentinvention further has a central thickness T on the optical axis 4. Forexample, the first lens element 10 has a first lens element thicknessT₁, the second lens element 20 has a second lens element thickness T₂,the third lens element 30 has a third lens element thickness T₃, thefourth lens element 40 has a fourth lens element thickness T₄, the fifthlens element 50 has a fifth lens element thickness T₅ and the sixth lenselement 60 has a sixth lens element thickness T₆. Therefore, the totalthickness of all the lens elements in the optical imaging lens set 1along the optical axis 4 is T_(all)=T₁+T₂+T₃+T₄+T₅+T₆.

In addition, between two adjacent lens elements in the optical imaginglens set 1 of the present invention there is an air gap G along theoptical axis 4. For example, an air gap G₁₂ is disposed between thefirst lens element 10 and the second lens element 20, an air gap G₂₃ isdisposed between the second lens element 20 and the third lens element30, an air gap G₃₄ is disposed between the third lens element 30 and thefourth lens element 40, an air gap G₄₅ is disposed between the fourthlens element 40 and the fifth lens element 50 and an air gap G₅₆ isdisposed between the fifth lens element 50 and the sixth lens element60. Therefore, the sum of total five air gaps between adjacent lenselements from the first lens element 10 to the sixth lens element 60along the optical axis 4 is G_(aa)=G₁₂+G₂₃+G₃₄+G₄₅+G₅₆. Also, a distancefrom the first object-side 11 of the first lens element 10 facing towardthe object side 2 to an imaging plane 71 on the image side 3 along theoptical axis 4 is L_(tt).

First Example

Please refer to FIG. 1 which illustrates the first example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 2A for the longitudinal spherical aberration on the image plane 71of the first example; please refer to FIG. 2B for the astigmatic fieldaberration on the sagittal direction; please refer to FIG. 2C for theastigmatic field aberration on the tangential direction, and pleaserefer to FIG. 2D for the distortion aberration. The Y axis of thespherical aberration in each example is “field of view” for 1.0. The Yaxis of the astigmatic field and the distortion in each example standsfor “image height”.

The optical imaging lens set 1 of the first example has the first lenselement 10 made of a transparent glass material with refractive powerand five lens elements such as the second lens element 20, the thirdlens element 30, the fourth lens element 40, the fifth lens element 50and the sixth lens element 60 made of a transparent plastic material, afilter 70, an aperture stop 80, and an image plane 71. The aperture stop80 is provided between the third lens element 30 and the fourth lenselement 40. The filter 70 may be an infrared filter (IR cut filter) toprevent inevitable infrared in light reaching the image plane toadversely affect the imaging quality.

The first lens element 10 has negative refractive power. The object-sidesurface 11 of the first lens element 10 facing toward the object side 2is a convex surface and the image-side surface 12 of the first lenselement 10 facing toward the image side 3 is a concave surface. Both theobject-side surface 11 and the image-side 12 of the first lens element10 may be spherical surfaces.

The second lens element 20 has positive refractive power. Theobject-side surface 21 of the second lens element 20 facing toward theobject side 2 has a convex part 23 (convex optical axis part) in thevicinity of the optical axis and a convex part 24 (convex circularperiphery part) in a vicinity of its circular periphery. The image-sidesurface 22 of the second lens element 20 facing toward the image side 3has a concave part 26 (concave optical axis part) in the vicinity of theoptical axis and a concave part 27 (concave circular periphery part) ina vicinity of its circular periphery. In addition, both the object-sidesurface 21 and the image-side surface 22 of the second lens element 20are aspherical surfaces.

The third lens element 30 has positive refractive power, an object-sidesurface 31 of the third lens element 30 facing toward the object side 2and an image-side surface 32 of the third lens element 30 facing towardthe image side 3. The object-side surface 31 has a convex part 33(convex optical axis part) in the vicinity of the optical axis and aconvex part 34 (convex circular periphery part) in a vicinity of itscircular periphery. The image-side surface 32 is a convex surface. Inaddition, both the object-side surface 31 and the mage-side surface 32of the third lens element 30 are aspherical surfaces.

The fourth lens element 40 has negative refractive power. Theobject-side surface 41 of the fourth lens element 40 facing toward theobject side 2 has a convex part 43 (convex optical axis part) in thevicinity of the optical axis and a concave part 44 (concave circularperiphery part) in a vicinity of its circular periphery. The image-sidesurface 42 of the fourth lens element 40 facing toward the image side 3has a concave part 46 (concave optical axis part) in the vicinity of theoptical axis and a convex part 47 (convex circular periphery part) in avicinity of its circular periphery. In addition, both the object-sidesurface 41 and the image-side 42 of the fourth lens element 40 areaspherical surfaces.

The fifth lens element 50 has positive refractive power, an object-sidesurface 51 of the fifth lens element 50 facing toward the object side 2and an image-side surface 52 of the fifth lens element 50 facing towardthe image side 3. The image-side surface 52 has a convex part 56 (convexoptical axis part) in the vicinity of the optical axis and a convex part57 (convex circular periphery part) in a vicinity of its circularperiphery. Further, both the object-side surface 51 and the image-side52 of the fifth lens element 50 are aspherical surfaces.

The sixth lens element 60 has negative refractive power. The object-sidesurface 61 of the sixth lens element 60 facing toward the object side 2has a convex part 63 (convex optical axis part) in the vicinity of theoptical axis and a concave part 64 (concave circular periphery part) ina vicinity of its circular periphery. The image-side surface 62 of thesixth lens element 60 facing toward the image side 3 has a concave part66 (concave optical axis part) in the vicinity of the optical axis and aconvex part 67 (convex circular periphery part) in a vicinity of itscircular periphery. In addition, both the object-side surface 61 and theimage-side 62 of the sixth lens element 60 are aspherical surfaces. Thefilter 70 may be an infrared cut filter, and is disposed between thesixth lens element 60 and the image plane 71.

In the optical imaging lens element 1 of the present invention, theobject side 21/31/41/51/61 and image side 22/32/42/52/62 from the secondlens element 20 to the sixth lens element 60, total of ten surfaces areall aspherical. These aspheric coefficients are defined according to thefollowing formula:

${Z(Y)} = {{\frac{Y^{2}}{R}/\left( {1 + \sqrt{1 - {\left( {1 + K} \right)\frac{Y^{2}}{R^{2}}}}} \right)} + {\sum\limits_{i = 1}^{n}\;{a_{2\; i} \times Y^{2\; i}}}}$

In which:

R represents the curvature radius of the lens element surface;

Z represents the depth of an aspherical surface (the perpendiculardistance between the point of the aspherical surface at a distance Yfrom the optical axis and the tangent plane of the vertex on the opticalaxis of the aspherical surface);

Y represents a vertical distance from a point on the aspherical surfaceto the optical axis;

K is a conic constant;

a_(2i) is the aspheric coefficient of the 2i order.

The optical data of the first example of the optical imaging lens set 1are shown in FIG. 20 while the aspheric surface data are shown in FIG.21. In the following examples of the optical imaging lens set, thef-number of the entire optical lens element system is Fno, HFOV standsfor the half field of view which is half of the field of view of theentire optical lens element system, and the unit for the curvatureradius, the thickness and the focal length is in millimeters (mm), and Fis a system focal length E_(fl) of the optical imaging lens set 1. Thelength of the optical imaging lens set is 12.306 mm (from the firstobject-side surface to the image plane along the optical axis). Theimage height is 2.143 mm. Some important ratios of the first example areas follows:

L_(tt)/G_(aa)=4.185

L_(tt)/T_(all)=1.633

L_(tt)/T₁=17.580

L_(tt)/T₂=5.764

L_(tt)/G₂₃=18.645

L_(tt)/T₃=5.798

L_(tt)/G₃₄=19.392

L_(tt)/T₅=6.345

T_(all)/T₂=3.530

T_(all)/G₂₃=11.418

T_(all)/G₃₄=11.875

T_(all)/T₅=3.886

G_(aa)/G₂₃=4.455

G_(aa)/T₄=8.674

Second Example

Please refer to FIG. 3 which illustrates the second example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 4A for the longitudinal spherical aberration on the image plane 71of the second example; please refer to FIG. 4B for the astigmaticaberration on the sagittal direction; please refer to FIG. 4C for theastigmatic aberration on the tangential direction, and please refer toFIG. 4D for the distortion aberration. The second example is similarwith the first example except that the second lens element 20 hasnegative refractive power, and the image-side surface 52 has a concavepart 57′ (concave circular periphery part) in a vicinity of its circularperiphery. The optical data of the third example of the optical imaginglens set are shown in FIG. 22 while the aspheric surface data are shownin FIG. 23. The length of the optical imaging lens set is 12.805 mm. Theimage height is 2.195 mm. Some important ratios of the second exampleare as follows:

L_(tt)/G_(aa)=2.422

L_(tt)/T_(all)=2.164

L_(tt)/T₁=21.342

L_(tt)/T₂=8.526

L_(tt)/G₂₃=5.586

L_(tt)/T₃=6.848

L_(tt)/G₃₄=14.103

L_(tt)/T₅=10.177

T_(all)/T₂=3.941

T_(all)/G₂₃=2.582

T_(all)/G₃₄=6.518

T_(all)/T₅=4.703

G_(aa)/G₂₃=2.307

G_(aa)/T₄=13.625

Third Example

Please refer to FIG. 5 which illustrates the third example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 6A for the longitudinal spherical aberration on the image plane 71of the second example; please refer to FIG. 6B for the astigmaticaberration on the sagittal direction; please refer to FIG. 6C for theastigmatic aberration on the tangential direction, and please refer toFIG. 6D for the distortion aberration. The third example is similar withthe first example except that the second lens element 20 has negativerefractive power, and the image-side surface 42 of the fourth lenselement 40 has a concave part 47′ (concave circular periphery part) in avicinity of its circular periphery. The optical data of the thirdexample of the optical imaging lens set are shown in FIG. 24 while theaspheric surface data are shown in FIG. 25. The length of the opticalimaging lens set is 10.63 mm. The image height is 1.981 mm. Someimportant ratios of the third example are as follows:

L_(tt)/G_(aa)=1.947

L_(tt)/T_(all)=2.896

L_(tt)/T₁=21.259

L_(tt)/T₂=20.492

L_(tt)/G₂₃=4.608

L_(tt)/T₃=11.746

L_(tt)/G₃₄=12.014

L_(tt)/T₅=9.167

T_(all)/T₂=7.075

T_(all)/G₂₃=1.591

T_(all)/G₃₄=4.148

T_(all)/T₅=3.165

G_(aa)/G₂₃=2.367

G_(aa)/T₄=18.251

Fourth Example

Please refer to FIG. 7 which illustrates the fourth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 8A for the longitudinal spherical aberration on the image plane 71of the second example; please refer to FIG. 8B for the astigmaticaberration on the sagittal direction; please refer to FIG. 8C for theastigmatic aberration on the tangential direction, and please refer toFIG. 8D for the distortion aberration. The fourth example is similarwith the first example except that the image-side surface 22 of thesecond lens element 20 facing toward the image side 3 has a concave part26 (concave optical axis part) in the vicinity of the optical axis, aconcave part 27 (concave circular periphery part) in a vicinity of itscircular periphery and a convex part 28 between the concave optical axispart and the concave circular periphery part, and the image-side surface52 of the fifth lens element 50 has a concave part 57′ (concave circularperiphery part). The optical data of the fourth example of the opticalimaging lens set are shown in FIG. 26 while the aspheric surface dataare shown in FIG. 27. The length of the optical imaging lens set is11.787 mm. The image height is 2.268 mm. Some important ratios of thefourth example are as follows:

L_(tt)/G_(aa)=4.672

L_(tt)/T_(all)=1.568

L_(tt)/T₁=16.839

L_(tt)/T₂=5.879

L_(tt)/G₂₃=17.859

L_(tt)/T₃=5.191

L_(tt)/G₃₄=34.497

L_(tt)/T₅=6.179

T_(all)/T₂=3.748

T_(all)/G₂₃=11.387

T_(all)/G₃₄=21.994

T_(all)/T₅=3.940

G_(aa)/G₂₃=3.822

G_(aa)/T₄=7.591

Fifth Example

Please refer to FIG. 9 which illustrates the fifth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 10A for the longitudinal spherical aberration on the image plane 71of the second example; please refer to FIG. 10B for the astigmaticaberration on the sagittal direction; please refer to FIG. 10C for theastigmatic aberration on the tangential direction, and please refer toFIG. 10D for the distortion aberration. The fifth example is similarwith the first example except that the image-side surface 22 of thesecond lens element 20 facing toward the image side 3 has a convex part27′ (convex circular periphery part) in a vicinity of its circularperiphery. The optical data of the fifth example of the optical imaginglens set are shown in FIG. 28 while the aspheric surface data are shownin FIG. 29. The length of the optical imaging lens set is 11.256 mm. Theimage height is 2.343 mm. Some important ratios of the fifth example areas follows:

L_(tt)/G_(aa)=3.918

L_(tt)/T_(all)=1.687

L_(tt)/T₁=16.080

L_(tt)/T₂=8.368

L_(tt)/G₂₃=16.553

L_(tt)/T₃=5.136

L_(tt)/G₃₄=28.107

L_(tt)/T₅=6.234

T_(all)/T₂=4.960

T_(all)/G₂₃=9.812

T_(all)/G₃₄=16.660

T_(all)/T₅=3.695

G_(aa)/G₂₃=4.225

G_(aa)/T₄=8.720

Sixth Example

Please refer to FIG. 11 which illustrates the sixth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 12A for the longitudinal spherical aberration on the image plane 71of the second example; please refer to FIG. 12B for the astigmaticaberration on the sagittal direction; please refer to FIG. 12C for theastigmatic aberration on the tangential direction, and please refer toFIG. 12D for the distortion aberration. The sixth example is similarwith the first example except that the second lens element 20 hasnegative refractive power, a convex part 27′ (convex circular peripherypart) in a vicinity of its circular periphery, the image-side surface 42of the fourth lens element 40 has a concave part 47′ (concave circularperiphery part) in a vicinity of its circular periphery and theimage-side surface 52 of the fifth lens element 50 has a concave part57′ (concave circular periphery part) in a vicinity of its circularperiphery. The optical data of the sixth example of the optical imaginglens set are shown in FIG. 30 while the aspheric surface data are shownin FIG. 31. The length of the optical imaging lens set is 10.803 mm. Theimage height is 1.977 mm. Some important ratios of the sixth example areas follows:

L_(tt)/G_(aa)=2.088

L_(tt)/T_(all)=2.616

L_(tt)/T₁=21.605

L_(tt)/T₂=18.793

L_(tt)/G₂₃=4.823

L_(tt)/T₃=8.310

L_(tt)/G₃₄=13.571

L_(tt)/T₅=9.238

T_(all)/T₂=7.185

T_(all)/G₂₃=1.844

T_(all)/G₃₄=5.188

T_(all)/T₅=3.532

G_(aa)/G₂₃=2.309

G_(aa)/T₄=17.353

Seventh Example

Please refer to FIG. 13 which illustrates the seventh example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 14A for the longitudinal spherical aberration on the image plane 71of the second example; please refer to FIG. 14B for the astigmaticaberration on the sagittal direction; please refer to FIG. 14C for theastigmatic aberration on the tangential direction, and please refer toFIG. 14D for the distortion aberration. The seventh example is similarwith the first example except that the second lens element 20 has aconvex part 27′ (convex circular periphery part) in a vicinity of itscircular periphery. The optical data of the seventh example of theoptical imaging lens set are shown in FIG. 32 while the aspheric surfacedata are shown in FIG. 33. The length of the optical imaging lens set is10.8 mm. The image height is 1.916 mm. Some important ratios of thesixth example are as follows:

L_(tt)/G_(aa)=2.068

L_(tt)/T_(all)=2.618

L_(tt)/T₁=21.600

L_(tt)/T₂=16.415

L_(tt)/G₂₃=4.754

L_(tt)/T₃=9.679

L_(tt)/G₃₄=14.272

L_(tt)/T₅=8.703

T_(all)/T₂=6.270

T_(all)/G₂₃=1.816

T_(all)/G₃₄=5.451

T_(all)/T₅=3.324

G_(aa)/G₂₃=2.298

G_(aa)/T₄=16.303

Eighth Example

Please refer to FIG. 15 which illustrates the eighth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 16A for the longitudinal spherical aberration on the image plane 71of the eighth example; please refer to FIG. 16B for the astigmaticaberration on the sagittal direction; please refer to FIG. 16C for theastigmatic aberration on the tangential direction, and please refer toFIG. 16D for the distortion aberration. The eighth example is similarwith the first example except that the object-side surface 11 of thefirst lens element 10 is a concave surface, the image-side surface 22 ofthe second lens element 20 has a convex part 27′ (convex circularperiphery part) in a vicinity of its circular periphery, and theimage-side surface 62 of the sixth lens element 60 has a concave part67′ (concave circular periphery part) in a vicinity of its circularperiphery. The optical data of the eighth example of the optical imaginglens set are shown in FIG. 34 while the aspheric surface data are shownin FIG. 35. The length of the optical imaging lens set is 10.804 mm. Theimage height is 1.835 mm. Some important ratios of the fifth example areas follows:

L_(tt)/G_(aa)=2.110

L_(tt)/T_(all)=2.576

L_(tt)/T₁=21.609

L_(tt)/T₂=16.341

L_(tt)/G₂₃=4.724

L_(tt)/T₃=9.480

L_(tt)/G₃₄=12.966

L_(tt)/T₅=8.629

T_(all)/T₂=6.345

T_(all)/G₂₃=1.834

T_(all)/G₃₄=5.034

T_(all)/T₅=3.350

G_(aa)/G₂₃=2.238

G_(aa)/T₄=14.596

Some important ratios in each example are shown in FIG. 36.

In the light of the above examples, the inventors observe the followingfeatures:

1) In each one of the above examples, the longitudinal sphericalaberration, the astigmatic aberration and the distortion aberration arerespectively less than ±0.04 mm, ±0.2 mm and ±30%. By observing thelongitudinal spherical aberration of each example, it is suggested thatall curves of every wavelength are close to one another, which revealsoff-axis light of different heights of every wavelength all concentrateson the image plane, and deviations of every curve also reveal thatoff-axis light of different heights are well controlled so the examplesdo improve the spherical aberration, the astigmatic aberration and thedistortion aberration. 2) In addition, the distances amongst the threerepresenting different wavelengths are pretty close to one another,which means the present invention is able to concentrate light of thethree representing different wavelengths so that the aberration isgreatly improved.3) The system total length of the examples is smaller than 13.0 mm. Thedemonstrated first example may maintain a good optical performance andreduced lens set length to realize a smaller product design andexcellent image quality.

In addition, it is found that there are some better ratio ranges fordifferent optical data according to the above various important ratios.Better ratio ranges help the designers to design the better opticalperformance and an effectively reduced length of a practically possibleoptical imaging lens set. For example:

1. L_(tt)/G₂₃≦20.0. When L_(tt)/G₂₃≦20.0, the reduction ratio of the gapG₂₃ with respect to the total length L_(tt) is smaller so the secondlens element 20 and the third lens element 30 may keep a better air gapG₂₃ to enhance a good image quality. Preferably, it is suggested that4.0≦L_(tt)/G₂₃≦20.0.2. L_(tt)/T₅≦11.0. If L_(tt)/T₅≦11.0, it means that the reduction ratioof T₅ with respect to the total length L_(tt) is less. However,considering optical properties and fabrication capability, thisrelationship satisfies a better arrangement. Preferably, it is suggestedthat 6.0≦L_(tt)/T₅≦11.0.3. T_(all)/G₂₃≦10.0. When T_(all)/G₂₃≦10.0, the reduction ratio of thegap G₂₃ with respect to the total length T_(all) is smaller so thesecond lens element 20 and the third lens element 30 may keep a betterair gap G₂₃ to enhance a good image quality. Preferably, it is suggestedthat 1.0≦T_(all)/G₂₃≦10.0.4. L_(tt)/T_(all)≦3.0. When L_(tt)/T_(all)≦3.0, it means that thereduction ratio of T_(all) with respect to the total length L_(tt) issmaller. However, considering optical properties and fabricationcapability, this relationship satisfies a better arrangement. It issuggested that 1.0≦L_(tt)/T_(all)≦3.0.5. T_(all)/T₅≦5.0. When T_(all)/T₅≦5.0, it means that the reductionratio of T₅ with respect to the total gap T_(all) is smaller. However,considering optical properties and fabrication capability, thisrelationship satisfies a better arrangement. It is suggested that3.0≦T_(all)/T₅≦5.0.6. G_(aa)/G₂₃≦4.5. When G_(aa)/G₂₃≦4.5, it means that the reductionratio of G₂₃ with respect to G_(aa) is smaller so the second lenselement 20 and the third lens element 30 may keep a better air gap G₂₃to enhance a good image quality. Preferably, it is suggested that2.0≦G_(aa)/G₂₃≦4.5.7. L_(tt)/T₁≦23.0. Because the first lens element 10 provides refractivepower, a thicker T₁ is much harder to become thinner. WhenL_(tt)/T₁≦23.0, it means that L_(tt) is reduced more to have smallertotal length and better optical quality. Preferably, it is suggestedthat 15.0≦L_(tt)/T₁≦23.0.8. T_(all)/G₃₄≦23.0. When T_(all)/G₃₄≦23.0, the reduction ratio of thegap G₃₄ with respect to the total length T_(all) is smaller so the thirdlens element 30 and the fourth lens element 40 may keep a better air gapG₃₄ to enhance a good image quality. Preferably, it is suggested that4.0≦T_(all)/G₃₄≦23.0.9. T_(all)/T₂7.5. When T_(all)/T₂≦7.5, it means that the reduction ratioof T₂ with respect to the total length T_(all) is smaller. However,considering optical properties and fabrication capability, thisrelationship satisfies a better arrangement. Preferably, it is suggestedthat 3.0≦T_(all)/T₂≦7.5.10. L_(tt)/G₃₄≦35.0. When L_(tt)/G₃₄≦35.0, it means that the reductionratio of G₃₄ with respect to the total length L_(tt) is smaller so thethird lens element 30 and the fourth lens element 40 may keep a betterair gap G₃₄ to enhance the image quality. Preferably, it is suggestedthat 11.0≦L_(tt)/G₃₄≦35.0.11. L_(tt)/T₂≦17.0. When L_(tt)/T₂≦17.0, it means that the reductionratio of T₂ with respect to the total length L_(tt) is smaller. However,considering optical properties and fabrication capability, thisrelationship satisfies a better arrangement. Preferably, it is suggestedthat 5.0≦T_(tt)/T₂≦17.0.12. L_(tt)/T₃≦8.5. When L_(tt)/T₃≦8.5, it means that the reduction ratioof T₃ with respect to the total length L_(tt) is smaller. However,considering optical properties and fabrication capability, thisrelationship satisfies a better arrangement. Preferably, it is suggestedthat 5.0≦L_(tt)/T₃≦8.5.13. L_(tt)/G_(aa)≦5.0. When L_(tt)/G_(aa)≦5.0, it means that thereduction ratio of G_(aa) with respect to the total length L_(tt) issmaller. However, considering optical properties and fabricationcapability, this relationship satisfies a better arrangement.Preferably, it is suggested that 1.5≦L_(tt)/G_(aa)≦50.14. 8.5≦G_(aa)/T₄. When 8.5≦G_(aa)/T₄, it means that the reduction ratioof T₄ with respect to G_(aa) is larger. However, considering opticalproperties and fabrication capability, this relationship satisfies abetter arrangement. It is suggested that 8.5≦G_(aa)/T₄≦20.0.

The optical imaging lens set 1 of the present invention may be appliedto a portable electronic device. Please refer to FIG. 18. FIG. 18illustrates a first preferred example of the optical imaging lens set 1of the present invention for use in a portable electronic device 100.The portable electronic device 100 includes a case 110, and an imagemodule 120 mounted in the case 110. A mobile phone is illustrated inFIG. 18 as an example, but the portable electronic device 100 is notlimited to a mobile phone.

As shown in FIG. 18, the image module 120 includes the optical imaginglens set 1 as described above. FIG. 18 illustrates the aforementionedfirst example of the optical imaging lens set 1. In addition, theportable electronic device 100 also contains a barrel 130 for theinstallation of the optical imaging lens set 1, a module housing unit140 for the installation of the barrel 130, a substrate 172 for theinstallation of the module housing unit 140 and an image sensor 70disposed at the substrate 172, and at the image side 3 of the opticalimaging lens set 1. The image sensor 70 in the optical imaging lens set1 may be an electronic photosensitive element, such as a charge coupleddevice or a complementary metal oxide semiconductor element. The imageplane 71 forms at the image sensor 70.

The image sensor 70 used here is a product of chip on board (COB)package rather than a product of the conventional chip scale package(CSP) so it is directly attached to the substrate 172, and protectiveglass is not needed in front of the image sensor 70 in the opticalimaging lens set 1, but the present invention is not limited to this.

To be noticed in particular, the optional filter 70 may be omitted inother examples although the optional filter 70 is present in thisexample. The case 110, the barrel 130, and/or the module housing unit140 may be a single element or consist of a plurality of elements, butthe present invention is not limited to this.

Each one of the six lens elements 10, 20, 30, 40 and 50 with refractivepower is installed in the barrel 130 with air gaps disposed between twoadjacent lens elements in an exemplary way. The module housing unit 140has a lens element housing 141, and an image sensor housing 146installed between the lens element housing 141 and the image sensor 70.However in other examples, the image sensor housing 146 is optional. Thebarrel 130 is installed coaxially along with the lens element housing141 along the axis I-I′, and the barrel 130 is provided inside of thelens element housing 141.

Because the optical imaging lens set 1 of the present invention may beas short as 13.0 mm, this ideal length allows the dimensions and thesize of the portable electronic device 100 to be smaller and lighter,but excellent optical performance and image quality are still possible.In such a way, the various examples of the present invention satisfy theneed for economic benefits of using less raw materials in addition tosatisfy the trend for a smaller and lighter product design andconsumers' demands.

Please also refer to FIG. 19 for another application of theaforementioned optical imaging lens set 1 in a portable electronicdevice 200 in the second preferred example. The main differences betweenthe portable electronic device 200 in the second preferred example andthe portable electronic device 100 in the first preferred example are:the lens element housing 141 has a first seat element 142, a second seatelement 143, a coil 144 and a magnetic component 145. The first seatelement 142 is for the installation of the barrel 130, exteriorlyattached to the barrel 130 and disposed along the axis I-I′. The secondseat element 143 is disposed along the axis I-I′ and surrounds theexterior of the first seat element 142. The coil 144 is provided betweenthe outside of the first seat element 142 and the inside of the secondseat element 143. The magnetic component 145 is disposed between theoutside of the coil 144 and the inside of the second seat element 143.

The first seat element 142 may pull the barrel 130 and the opticalimaging lens set 1 which is disposed inside of the barrel 130 to movealong the axis I-I′, namely the optical axis 4 in FIG. 1. The imagesensor housing 146 is attached to the second seat element 143. Thefilter 70, such as an infrared filter, is installed at the image sensorhousing 146. Other details of the portable electronic device 200 in thesecond preferred example are similar to those of the portable electronicdevice 100 in the first preferred example so they are not elaboratedagain.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. An optical imaging lens set, comprising: a firstlens element, a second lens element, a third lens element, a fourth lenselement, a fifth lens element and a sixth lens element from an objectside toward an image side in order along an optical axis and each lenselement has an object-side surface facing toward said object side andallowing imaging light to pass through as well as an image-side surfacefacing toward said image side and allowing said imaging light to passthrough, wherein: said first lens element has negative refractive power;said second lens element has a second object-side surface with a convexportion in a vicinity of a circular periphery of said second lenselement; said third lens element has a third object-side surface with aconvex portion in a vicinity of a circular periphery of said third lenselement; said fourth lens element has refractive power; said fifth lenselement has a fifth image-side surface with a convex portion in avicinity of said optical axis; and said sixth lens element has a sixthobject-side surface with a concave portion in a vicinity of a circularperiphery of said sixth lens element, wherein said optical imaging lensset exclusively has six lens elements with refractive power, and adistance L_(tt) from said first object-side surface to an imaging planeon said image side along said optical axis and an air gap G₂₃ betweensaid second lens element and said third lens element along said opticalaxis satisfy a relationship L_(tt)/G₂₃≦20.0.
 2. The optical imaging lensset of claim 1, wherein a total thickness T_(all) of said first lenselement, said second lens element, said third lens element, said fourthlens element, said fifth lens element and said sixth lens element alongsaid optical axis satisfies a relationship T_(all)/G₂₃≦10.0.
 3. Theoptical imaging lens set of claim 2, satisfying a relationshipL_(tt)/T_(all)≦3.0.
 4. The optical imaging lens set of claim 3, whereina thickness T₅ of said fifth lens element along said optical axissatisfies a relationship T_(all)/T₅≦11.0.
 5. The optical imaging lensset of claim 1, wherein the sum of all four air gaps G_(aa) between eachlens element from said first lens element to said sixth lens elementalong the optical axis satisfies a relationship G_(aa)/G₂₃≦4.5.
 6. Theoptical imaging lens set of claim 5, wherein a thickness T₁ of saidfirst lens element along said optical axis satisfies a relationshipL_(tt)/T₁≦23.0.
 7. The optical imaging lens set of claim 1, wherein atotal thickness T_(all) of said first lens element, said second lenselement, said third lens element, said fourth lens element, said fifthlens element and said sixth lens element along said optical axis and anair gap G₃₄ between said third lens element and said fourth lens elementalong said optical axis satisfy a relationship T_(all)/G₃₄≦23.0.
 8. Theoptical imaging lens set of claim 7, wherein a thickness T₂ of saidsecond lens element along said optical axis satisfies a relationshipT_(all)/T₂≦7.5.
 9. The optical imaging lens set of claim 8, wherein athickness T₁ of said first lens element along said optical axissatisfies a relationship L_(tt)/T₁≦23.0.
 10. The optical imaging lensset of claim 1, wherein an air gap G₃₄ between said third lens elementand said fourth lens element along said optical axis satisfies arelationship L_(tt)/G₃₄≦35.0.
 11. The optical imaging lens set of claim10, wherein a thickness T₂ of said second lens element along saidoptical axis satisfies a relationship L_(tt)/T₂≦17.0.
 12. The opticalimaging lens set of claim 11, wherein a thickness T₃ of said third lenselement along said optical axis satisfies a relationship L_(tt)/T₃≦8.5.13. The optical imaging lens set of claim 1, wherein the sum of all fiveair gaps G_(aa) between each lens element from said first lens elementto said sixth lens element along the optical axis satisfies arelationship L_(tt)/G_(aa)≦5.0.
 14. The optical imaging lens set ofclaim 13, wherein a thickness T₄ of said fourth lens element along saidoptical axis satisfies a relationship 8.5≦G_(aa)/T₄.
 15. The opticalimaging lens set of claim 14, wherein a thickness T₅ of said fifth lenselement along said optical axis satisfies a relationship L_(tt)/T₅≦11.0.16. An electronic device, comprising: a case; and an image moduledisposed in said case and comprising: an optical imaging lens set ofclaim 1; a barrel for the installation of said optical imaging lens set;a module housing unit for the installation of said barrel; a substratefor the installation of said module housing unit; and an image sensordisposed at an image side of said optical imaging lens set.
 17. Theoptical imaging lens set of claim 1, wherein a thickness T₅ of saidfifth lens element along said optical axis satisfies a relationshipL_(tt)/T₅≦11.0.